You have both put yourselves in a good position with your grades and SAT scores, but those things are merely a good start and will by no means carry you through recruitment. Your personalities have to shine.
Like others have said, talk to your twin and establish "ground rules", namely:
-Are you going to tell chapters that you are a package deal, that you're willing to pledge different chapters, or not say anything?
-Depending on your answer above, will you and your twin tell each other your opinions of each chapter or keep everything a secret?
It is very possible that a chapter may be interested in just one of you, even if you are both very similar. This is mainly because your rusher may be random. If both of you talked to the same people at each chapter, each chapter would probably like you the same. However, one of you might totally hit it off with your rusher at one chapter and the other not so much, which will result in different invitations for the next round. Also, because you will have different rushers at each chapter, YOUR perceptions of the same chapter may very well be different.
Consider these two scenarios:
-You fall in love with a chapter, and you're going there for preference night. However, your twin either didn't like the chapter or got cut. Would you not want to be in this chapter if your twin couldn't be in it with you?
-Same scenario as above, only it's your twin in love with a particular chapter and you who didn't like it or got cut. Would you want your twin to not join for you?
I'm sure some chapters like the idea of pledging twins, but of course there are no guarantees with each chapters' membership selection procedures. I can think of many sets of twins in many chapters at my school, twins that joined different chapters, plus a set of triplets--they split up 2 and 1.
ETA: Here is a
late 1980s retro thread about twins rushing together. The twins decide not to tell each other anything and still end up at the same chapter!
Good luck to you and your twin and may both of you find a great sisterhood, regardless of whether it is the same one!